A H.«-k •..•:"
Test B.ir- t
FIG. 137. i<ly f«»r placing i» Casting Pit and set as at K, pages 550 and 552and up in a green state; so little that, in making the larger cores, rodding was very necessary, in order to hold, the cores together. When this mixture is dry the cores are exceptionally strong to handle, but crush very easily when the castings commence to contract. To form the small neck in the green sand tensile test bars as at D, Fig. 133, cores made of the above mixture were used as at F above, Fig. 136. This division in the tensile test bars was made for the purpose of giving a long and very short test specimen.